Process for manufacturing multi-walled vessels

Abstract

A method of manufacturing a double-walled vessel comprises: a) providing an inner hollow body ( 5 ); b) mounting the inner hollow body ( 5 ) in a rotational mould ( 1 ) with the external surface of the inner body spaced from the internal surface of the mould; and c) rotationally moulding a hollow plastics outer body around, and spaced from the inner body in such a manner as to join the inner and outer bodies together at at least one predetermined location.

1 . A method of manufacturing a double-walled vessel comprising: 
 a) providing an inner hollow body;    b) mounting the inner hollow body in a rotational mould with the external surface of the inner body spaced from the internal surface of the mould; and    c) rotationally moulding a hollow plastics outer body around, and spaced from the inner body in such a manner as to join the inner and outer bodies together at at least one predetermined location.    
     
     
         2 . A method according to  claim 1 , comprising moulding the inner body from plastics material.  
     
     
         3 . A method according to  claim 2 , comprising rotationally moulding the inner body.  
     
     
         4 . A method according to  claim 1 ,  2  or  3 , comprising forming the inner body with a plurality of external projections extending from the surface thereof such that the inner surface of the outer body becomes joined to the projections.  
     
     
         5 . A method according to any preceding claim, wherein the internal surface of the mould is formed with a plurality of inwardly-directed projections such that the outer body moulded thereon has inwardly-directed projections which are joined to the outer surface of the inner body.  
     
     
         6 . A method according to  claim 5 , wherein the inner body is formed with external projections and the internal surface of the mould is formed with inwardly-directed projections corresponding in position with at least some of the external projections such that the outer body is moulded with inwardly-directed projections joined to external projections on the inner body.  
     
     
         7 . A method according to any of claims  4 ,  5  and  6 , wherein at least some of the projections are in the form of ribs.  
     
     
         8 . A method according to any preceding claim, which comprises forming an initial skin of plastics material on the surface of the mould, and then introducing into the space between the skin and the inner body plastics material containing a blowing agent, thereby providing expanded plastics material in said space bonded to the outer body.  
     
     
         9 . A method according to any preceding claim, wherein the inner body has a single opening into the interior thereof smaller than the maximum cross-sectional area of the body, and the outer body is moulded in such a manner as to be sealed to inner body around the opening.  
     
     
         10 . A method of manufacturing a multi-walled vessel, comprising forming a double-walled vessel in accordance with a method according to any preceding claim, mounting the double-walled vessel in a rotational mould with the external surface of said vessel spaced from the internal surface of the mould, and rotationally moulding a hollow plastics outer body around, and spaced from, the double-walled vessel in such a manner as to join the inner vessel and the outer body together at at least one predetermined location.